Grinding machine



Oct. 10, 1944. M JEL S 2,360,235

GRINDING MACHINE Filed June 10, 1943 2 Sheet-Sheei 1 Oct. 10, 1944. M. JELLIS GRINDING MACHINE 2 Sheets-Sheet 2 Filed June 10, 1943 Fla:

atented Oct. 1944 Morgan J ellls, to Coventry Peterborough, England, assignor Gauge & Tool Company Limited,

Fletchamstead, Coventry, England Application June 10', 1943, Serial No. 490,316 In Great Britain August 14, 1942 9 Claims. oni. 51-123) This invention relates to the production of gear tooth and like ;ion in which a spiral ribbed grinding wheel proiled to the rack form of the pitch desired is em- J yed.

The object of the present invention is to provide an improved machine embodying this principle. t r

A further object of the invention is to provide an improved arrangement for distributing the wear uniformly across the full width of the grinding wheel.

The invention also has for its objects to avoid overrun or idle strokes and backlash and reversing shocks; thereby eliminating loss of time and contributing to long life and accuracy of the machine.

According to the present invention the improved machine is chara'cterized in that, in addition to its normal rotation in timed relation with the grinding wheel, the work blank is moved laterally to and fro across the wheel with a rolling motion so as todistribute the wear uniformly across the full width of the wheel and at the same time to ensure accuracy of the involute profile of the gear teeth.

In the accompanying drawings,

Figure 1 illustrates a lay present invention.

Figure 2 is a detail view of the mechanism employed for traversing the work blank across the grinding wheel and at the same time giving it a rolling motion.

Figure 3 is a view similar to Figure 1 ol an alternative construction.

Figure 4 is a detail view of alternative means for rolling the work-blank in engagement with the grinding wheel.

Referring to the drawings, 2 represents the grinding wheel and 3 the work-blank in which gear tooth or like profiles are to be produced by a grinding operation.

The grinding wheel spindle! is rotatably mounted in bearings 5 in a head stock 6 and can be driven at the desired speed in any suitable manner, as by means of a belt 1 andpulley 8 or an electric motor.

out embodying the profiles by a grinding operadie is rotatably mounted in the of the two worm gears has a sliding splined connection with its operating shaft ll and is in constant mesh with a worm wheel l8 fixed to a spinheadstock ll and having a sliding splined connection with the worm Id of the first gear. Meanapreferably independently driven, are provided for reciprocating the worm it axially relatively to its associated worm wheel i8, and at the same time for operating the work-head iii to move the work blank 3 to and fro in a lateral direction across the face of the helically ribbed grinding wheel 2.

For this purpose the said worm it which, as

shown in Figure 2, is in constant mesh with its worm wheel 18 and is rotatably mounted in lugs 28 on a slide 2i arranged and adapted for indenecting rod The work-spindle 9, which is rotatably mount- 7 ed in a work-head i0 slidably mounted in a fixed headstock II, is driven irom the wheel spindle 4 through a change speed gear II, by means or worm and wheel gears in one or which thewormwheel 13 is secured to the work-spindle the worm l4 rotatably mounted in'bearlngs IS in the work-head II. The worm IO 01' the other Sand pendent reciprocation On a guide plate 22 in a direction parallel with the axis of said worm it. At the same time the work-head it is moved bodily to and fro in the headstock H in a directionat right angles to the ams of the workspindle 9 by means of a stylus 23 on the workhead H3 co-operating sine bar may'be varied and is set by means of slip gauges equalling the pitch radius of the gear return movement of held in contact with to be ground. During the the work-head the stylus is 'the sine bar-by means of the tension spring 25- one' end of which is attached to the work-head and the other to the headstock H. The slide 2! may be independently operated in any suitable manner as by means of an electric motor or, as shown, bya disc crank 26 having an adjustable connection with the said slide by means of a con- 21, and driven by belt and pulley 28 through worm gear 29.

During the operation of the machine the work blank 3, in addition to its rotary motion in timed relation with the speed of rotation of the helicallyribbed grinding wheel 2, is rolledbackwards and forwards in engagement with the latter by the axial movement of the worm ii, the efiect of which is to alternately accelerate and retard the speed of rotation of the worm wheel 18 and hence the work-blank. At the same time the work blank is also traversed backwards and forwards across the face of the grinding wheel with a arallel motion by the co-action between the sine bar 24 on the slide 2! and the stylus 23 on the work-head Ill.

7 j In the alternative construction shown in Fig-. ure 3 in which parts corresponding with those shown in Figure 1 are designated by similar-reference numerals, the work-spindle 9 is driven in with a sine bar 25 carried.

The inclination of the timed relation with nism which for the ufacture may all N like profiles by a grinding an appropriately formed ;verse directions about the axis of of said spindle alternate the helically ribbed abrasive wheel 2, as before, except that in this case the arrangement of the drive necessitates the use of bevel gear 30, 3| between the worm l6 and the shaft I 1, and also the use of bevel gear 32, 33 between the worm wheel l8 and the worm gear I 3, I4 for the work-spindle 9. In order to provide for variations auxiliary change gears 34, 35 may be introduced into the drive between the worm wheel l8 and the spindle is of the worm l4, said gears being carried by the sliding work head In, as shown. The said alternative construction is also distinguished from that shown in Figure l in that the use of the sine bar 24 and slide 2| are dispensed with, the sliding work-head lll being in this case operated directly from the independently driven crank disc 26 by means of the adjustable connecting rod 21. The arrangement of the'worm and wheel gear l6, l8is also different, the worm in this case being mounted in the'work headstock ll, while the spindle 36 of the worm wheel is rotatably mounted in the sliding work-head l and together with the bevel gear 32, 33 and auxiliary change speed gear 34, 35 move therewith. In other respects the operation is the same as in Figure 1, that is to say, the work speed in relation to-the speed 01 the abrasive Wheel 2 during the reciprocating motion of the workhead [0, is modified by the angular displacement of the worm l6 and worm wheel l8 resulting from the axial travel of the latter along and in mesh with the axially stationary worm l 6. As shown in Figure 4 spiral gears 31, 38 may be substituted for the worm and wheel gear I6, l8

The grinding operation in the diameter or the work 3 is continuous, the work an appropriately remaining in contact with the grinding wheel until the operation of forming the gear teeth is completed.

'l'he mechanism of the machine is arranged for umdirectional rotation, a feature which is large- 1y responsible for the accuracy and durability of the improved machine.

Accuracy of division is not dependent upon a dividing plate but principally upon the accuracy of the worms and worm wheels of the mechabe made identical in pitch. I claim:

1. A machine for producing gear tooth and operation, comprising grinding wheel, a workblank h0lder,'mechanism .wheel, traversing means for traversing said workpurposes of facilitating man- I for rotating said work. blank holder in timed relation with said grinding like profiles by a grinding operation, comprisi formed grinding wheel, a W01 head, a spindle rotatably mounted insaid W01 head and adaptedto receive a work-blank, mec anism for rotating said grinding wheel and spi die in timed relation with each other, means a( ing independently of said mechanism for reci rocating' said work-head in a direction at rig angles to said spindle, and modifying means not ated by said independent means for superimpo ing upon the normal rotary movement of sa spindle alternate partial rotations in reverse d rections about the axis of said spindle.

4. A machine for producing gear tooth a: like profiles by a grinding'operation, comprisir an appropriately formed grinding wheel, a work spindle adapted to receive awork-blank, mecha nism for rotating said wheel and spindle in time relation with each other, said mechanism includ ing worm and wheel gear; means acting inde pendently of said mechanism for reciprocatin saidwork-head in a direction at right angles t said Spindle, and means associated with said in dependently acting means for reciprocating sail worm in an axial direction relatively to and ii mesh with its associated worm wheel. 1 i

.5. A machine for producing gear tooth an: like profiles by a grinding operation, comp an appropriately formed grinding wheel, a workhead, a spindle rotatably mounted in said workhead and adapted to receive a. work-blank, means for reciprocating said work-head in a direction at right angles to said spindle, and mechanism for rotating said grinding wheel and spindle in timed relation with each other, said mechanism including a worm wheel adapted for rolling onagement with an axially stationary worm during reciprocation of said work-head. v

6. A machine for producing gear tooth and like profiles by a grinding operation, comprising an appropriately formed grinding wheel, a workhead, a spindle rotatably mounted in said workhead and adapted to receive a work-blank, means for reciprocating said work-head in a direction at right angles to said spindle, and. mechanism for rotating said grinding timed relation with each other, said mechanism the direction of its axis with the other during reciprocation of said work-head.

7. A machine for producing gear tooth like profiles by a grinding operation, comprising a wheel head, an appropriately formed grinding.

therein, a work-head wheel 'rotatably mounted mounted for reciprocation in a direction parallel with the axis -of saidgrinding wheel, a spindle grinding wheel, and modifying means acting to 7' superimpose upon the normal rotary movement of said holder alternate partial rotations in resaid holder.

anism for rotatingfsaidwheel and spindle in timed relation with each other, a sliding workhead carrying said spindle, means associated with said mechanism and work -head for traversing the work-blank across the operative 1 face of the grinding wheel, and modifying means acting to superimpose-upon the normal rotary movement partial rotations in reverse directions about the-axis of said spindle.

. g 3. A machine ed to receive a work-blank,

rotatably mounted in said work-head and adaptmeohanism for rotating said grinding wheel and spindle in precontact between said stylus and sine bar.

8. A machine for producing gear tooth and like profiles by a grinding operation, comprising a wheel head, an appropriately formed grinding wheel rotatably mounted therein, a work-head mounted for reciprocation in a direction parallel with the axis of saidfgri'nding wheel, a spindle rotatably mounted in said work-head and adaptfor producing gear tooth and 7 ed to receive a work-blank, mechanism for rotatwheel and spindle in,

with each other, said ing said grinding wheel and spindle in pre-determined timed relation with each other, said mechanism including a worm wheel carried by said work-head, and in constant mesh with an axially stationary worm, and means acting independently of said mechanism for reciprocating said work-head.

9. A machine for producing gear tooth and like profiles by a grinding operation, 'said machine comprising an appropriately formed grinding wheel mounted for rotation about its axis, and a work holder for presenting the work-blank to the operative face of the grinding wheel, in combination with mechanism for positively actuating said work-holder to rotate the work-blank in timed relation with the rotation of said grinding wheel, independently operated means for traversing said work-blank across the operative face of said grinding wheel, and modifying means actuated by said independent means and acting to superimpose upon the normal rotary movement of said work-holder alternate partial rotations in reverse directions about the axis of said workpiece.

MORGAN JELLIS. 

